varsha 
vinay Resizing ext3 filesystem
cloudibee The ext3 filesystem on Linux can be resized using ext2online . This can only be done when the filesystem is online (mounted) and where the the filesystem is on a…
Windows provisioning from PXE
Two opensource solutions through which you can provision Windows servers by network booting from a Linux PXE : http://unattended.sourceforge.net/http://unattended-gui.sourceforge.net/ Good one & they worked for me.
NFS mount options
Some important nfs mount options in Linux. tcp – Specifies for the NFS mount to use the TCP protocol instead of UDP. rsize=8192 and wsize=8192 – These settings speed up…
Netapp Flexshare
A very good demo on Netapp Flexshare and how it impacts performance : http://www.netapp.com/ftp/flash/flexshare-demo/flexshare_demo.html
Know about /proc/meminfo
/proc/meminfo is one of the more commonly used files in the /proc/, as it reports a large amount of valuable information about the Linux system’s memory. Here is the brief…
Converting ext2 filesystem to ext3 filesystem
ext3 filesytem is a journal’d filesystem. The command “tune2fs“ can add a journal to an existing ext2 file system and convert it to ext3, without altering the data already on…
Network bonding : Part II ( modes of bonding )
The steps for creating network boding in Linux is available in http://unixfoo.blogspot.com/search/label/networking. RHEL bonding supports 7 possible “modes” for bonded interfaces. These modes determine the way in which traffic sent…
How to configure Linux machine as router?
Here are some simple steps to do it, using Network Address Translation (NAT) Enable packet forwarding . Make it permanent by adding “net.ipv4.ip_forward = 1” to /etc/sysctl.conf echo “1” >…
AIX tips : Switching to 64-bit kernel
The AIX kernel is available in 32-bit or 64-bit mode. If a 32-bit kernel is running and you want to switch to 64-bit kernel , use the following command. (…
Sticky bit
What is the “sticky bit”? (t and T) The sticky bit is primarily used on shared directories. It is useful for shared directories such as /var/tmp and /tmp/ because users…
Linux Benchmarking tools
Here is a list of few benchmarking tools put together Bonnie++ : This is a benchmark suite that is aimed at performing a number of simple tests of hard drive…
nmon : AIX and Linux performance monitoring tool
Nmon : A free performance monitoring script for Linux and AIX systems. It gives lot of performance information and can output the performance analysis results in many format. nmon Document…
What is Direct I/O
A file is simply a collection of data stored on media. When a process wants to access data from a file, the operating system brings the data into main memory,…
Kernel parameter : file-nr and file-max
file-max : The Linux Operating system kernel allocates file handles dynamically and the value in file-max denotes the maximum number of file handles that the Linux kernel will allocate. When…
Simple perl ipcalc
Here is a simple program to calculate Network address and broadcast address, given input of IP address and netmask. Perl code : #!/usr/bin/perl # Get ipaddress and netmask from user…